1. Field of the Invention
The present invention relates to a laminated inductor.
2. Description of the Related Art
As electronic devices become smaller and support multiple bandwidths in recent years, the market is demanding laminated inductors that are smaller, higher in Q, and offering narrower inductance steps and smaller induction deviation. With conventional laminated inductors, the coil is formed by combining multiple conductor patterns obtained from multiple screen masks, or combining multiple conductor patterns obtained by shifting identical screen masks. As the laminated inductor becomes smaller, the core area of its coil decreases and inductance drops, while at the same time the magnetic flux does not pass through as effectively and the inductor's Q-value drops as a result. FIG. 6 is a schematic exploded view of an example of laminated inductor based on prior art, where conductor patterns B21 to B29, B210 to B212 of specified shapes are formed on insulator layers A22 to A29, A210 to A213, respectively, and these conductor patterns are electrically connected by via hole conductors C21 to C29, C210 to C215, to constitute a laminated inductor comprising a coil conductor spirally formed in a laminate.
According to Patent Literature 1, multiple sets of a pair of ferrite sheets, each of which has a conductor pattern of the same shape and both of which are stacked one atop another to form a double-conductor pattern, are stacked together and the conductor patterns in adjoining sets are interconnected by column-shaped through holes at positions where the patterns cross each other at right angles, to form a double-coil conductor winding spirally. It is claimed that, according to the constitution of FIG. 6 and constitution described in Patent Literature 1, where coil wires are arranged and connected in parallel, rise of direct-current resistance can be prevented, while high Q-value can be achieved at the same time.